William h



at the central oiiice,for every purpose whatso- UNITED Srnrns ATENT@Erica WILLIAM II. Bonner AND .IoHN A. sEnLY, or New YORK, N. Y.

TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 288,627', datedNovember 20, 1883.

Application filed May 28, 1883. (No model.)

5 ofNew York, jointly, have invented a new and useful System forTelephonie Intercommuni'cation, of which the following isaspeciiication.

Our invention has Vfor its object the adapt-V ing of a seriesIof privatelines centering at an office common to all of them for telephonie use. I

In hotels the annunciator system commonly in use consists of a series ofelectrical conductors-onefor each guestroom-centering at anannunciator-board in the clerks office; and it is to such a system ofconductors that we adapt telephones, so that any guest may call .theclerk and communicate with him through the telephone, and so that theclerk may call a guest and communicate with him inlike manner, and alsoso that two individual wires may be joined at the clerks office, therebyenabling two guests to converse telephoni cally.

While we suggest the adaptability of our invention to annunciatorsystems of hotels, we also design it for useIin ordinary citytelephone-exchanges as well. I

In carrying out our invention we wholly dispense with the use of localbatteries in the guests rooms, both for the purpose of charging theprimary coil of the telephone-transmitters and for calling the clerk orattendant` at the central office; and, furthermore, we4

employ only a single battery, which is placed ever inthe system. Bymeans ot" this single battery theprimarycircuitsofallthetelephone- Itransmitters are supplied. Each guests line is 4o connected by the guestwith said battery to call the central ottico, and the centralofticeattendant can connect any individual line with the battery to call theguest to whoseroom it I communicates.

5o and which runs to all of the rooms y of the hotel.

'Ihe primary circuit ot' each guests transmita To the end ofaccomplishing these results we employ, in addition to the series of inting-telephone is included in said common circuit. The common circuit,or battery-circuit,77 as we will term it, is provided at each guestsroom with a normally-open branch,and said branch, by means of a key orswitch, may be joined to the correspondingindividual line, while at thesame time said individual line will be disconnected from its normalearthconnection. When the battery-circuit is thus joined to anindividual line by a guest or subscriber, acircuit is completed from thecentral ottce or station to the guests room,and thence back to thecentral ofiice and through an annunciator-drop. Theattendant at thecentral ofice may in like manner disconnect any two lines with eachother, and at the same time disconnecting said lines Vfrom theireartlrconnections at the central station.

T is an ordinary contacttransmitter, having an induction-coil, locatedat a central station, and T' and 'l2 are similar transmitters placed inthe rooms of different guests.

A is the battery-circuit, beginning at earth G and terminating at G',which embraces battery B and the primary coils of all of the telephonictransmitters in the system. Line A also includes a resistance, B, for apurpose to be hereinafter described.

Each room or subscriber is provided with an individual telephone-line,and in Fig. l two such lines are shown. rIlhe line C, Ebeginning at E,embraces the coils of annunciator-drop M, wire C', spring-jack N S, wireC?, telephone5 switch arm L, anvil zI, wire-C3, pushbutton or l `key K,anvil d, call-bell C B, and wire C4, thence passing to 4earth E'. Inlike manner the circuit of line D is completed 4i'rom E2, through MQN'S', D2, L', D, K', b, D, IG B', D5, to earth I IDO As the telephonieapparatus for each room i or subscriber is the saine as that of all theothers, a description of one will serve forall.

Each room or subscriberis provided with an automatic switch, whichoperates, when the telephone is out of use, to divert theindividuallinecircuit from the telephonie t-ransmitters and receiver, and to direct itthroughv a callbell, C B. Thus, when telephone-reeeiverI-I is hung uponlever L, said lever is depressed against the action of spring s intocontact with anvil h.,- but when the telephone is removed from the leverit is raised against contact-point g, and the-circuit or' line D iscompleted, not through call-bell C B to earth E, but instead throughwire 5, telephone-receiver H, wire 6, to binding-post 3, the secondarycoil of transmitter T', to binding-post 4 and wire 7, to earth Each lineand telephone set is also provided with a key or push-button, K, and, asshown in the drawings, when not depressed, the individual line iscompleted through C B to earth; but when depressed the individual lineis disconnected from the call-bell and is joined through stop c, wire11, to point i of battery-line A, and thereby, upon depressing key K, abattery-circuit is thrown on C from A, and station X is enabled to callup the centrai office.

At the central station, or clerks office, each line is provided with anannunciator-drop, as M,- to indicate a call from station X. Normally,line C is connected to earth through spring-jack N S; but afterreceiving a call from station X it is necessary that thecentralofficeattendant connect himself with station X by telephone toascertain what is wanted. For this purpose he depresses a lever-arm, L,and raises spring S against stop p, when line C from station X is brokenfrom M, and is completed through p f n F2, receiving-telephone I-I, wireF', binding-post 3 of transmityter T, the secondary coil of saidtransmitter,

binding-post 4 and F, to earth C. The centraloliice attendant havingdepressed lever L2, and thereby placed his telephone in circuit, and theoperator at station X having removed his telephone II from L, it isapparenty that words spoken into transmitter T will causecurrcnt-impulses in the primary coil vof T, `which in turn will set upimpulses in the secondary coil of said transmitter, thereby causing areproduction of speech in teleph one.-

wereceiver H. In the same manner, words utter-ed into transmitter T bythe central .operator will be reproduced in receiver H2., If the.central operator is apprised that thev operator. at X desires toconverse with Y, he turns a spring-jack plug or wedge, I, upon itscenter y, thus thrusting said plug betweenspring S and block N. Theupper portion 2 of the wedge isy of conducting material, while the loweris an insulating-piece. Vhen the wedge 'is pressed between` S and 'NQ itbeing connected by wires q and N2 to battery-line A atj, the individuallinefis first disrupted at the springjack, and is then connected to thebattery-line. By this means line D2 is charged with a current and bell CB is rung. The central operator may then inform Y what is wanted bytelephone upon depressing lever L3. The two subscribers at X and Ybeingin readiness to converse, wedge I is removed from the spring-jack, whenswitch-plugs V I and V I2, joined by conductor fr, are placed inspring-jacks N S and N S, and N S, N S, Y, and V being of metal, S and Sare con- In this way the two lines are disrupted at the central stationfrom their normal eartlrconnections and from their annunciator-drops Mand M, and are connected together through conducting-cord x.

When key K is depressed at station X, line C is connected to battery-line A, and inorder that a considerable current may be `obtained upon lineC from battery B, itis necessary that a resistance, It, be inserted inline A near its terminal G; otherwise the potential ofv points along A,near G, would be too low to cause C t'o receive sufficient current toopen ate annunciator M, and current from battery B, instead of flowingover C, would pass directly to earth G.

From the foregoing it is seen that the battery-circuit is permanentlyconnected to yall of the transmitters in the system, said line on thebattery side of the transmitters being connected to the primaries of theinduction-coils thereof at posts 1, while the other sides` are connectedto line A at post 2. The battery.l line, in addition to embracing theprimaryof the induction-coil foreach local station, is also provided atpointsi and t" and j, respectively, with normallycpen branches ll, l2,and N2; and in connection with branches 11- andv l2 there are keysv Kand K, respectively, which normally complete individual lines throughsaid bells at the local stations, while upon depressing K or K theindividual line in which it is placed is broken and diverted from thecallbell to the common battery circuit.

Branch N2 is also provided with means, as

shown, for breaking the individual lines from their normalearth-connections and connecting said individual lines by branch NIl tothe the central operator may be placed in con nection with anyparticular individual line,

the conductor F F F, containing the telephone transmitter and receiver,-is provided with as many `divergent branches ff as therey areindividuallines; and each of saidbranches, as f', may be connected to itsrespective line` through point p and spring S. In like man- IOO IIO

ters Patent, is-

l. A series of individual telephone-lines `which are unprovided withbatterycentering at a central station, in combination with a single linepermanently closed and provided with battery, running fromsaid centralstation to telephone-stations upon the individual lines,

and means for connecting the individual lines to the battery-line, asdescribed.

2. Aline joining a central station with a series of telephone-stations,which is permanently closed and provided with battery, and a series oftelephonie transmitters, in combination with a series of individualtelephonel'nes separately connecting the local stations with theceutralstation, and means for` joining the individual lines to thebattery-line, substantially as specified.

y 3. A telephonie line` permanently closed and provided with batterycommon to a cen-` tral station and a series of local stations, having ateach of said stations atelephonic transmitter and the primary coil of aninductorium formingasection or part of said line, in combination With aseries of independent individual `lilies centering rat the centralstation and sepater-inductorium to an individual line either at a localstation or at the central station.

4. 'As a means for enabling a telephonie system to be operated Withoutthe use of battery at local stations, the combination of one line havingan earth return closed and permanently provided with` battery at thecenbattery-line.

5. The combination of a series of individual telephone-lines, each ofwhich is provided at a local station with a call-bell or signalingdevice normally in circuit, and a key or pushbutton for connecting saidindividual line with a common battery-line, (said commonbattery-linebeing permanently closed and provided vvith battery,) andfor removing the call-bell from circuit, and a common batterylinewhereby a local station may be called up, and may also call the centralstations, as

described.

6. In combination with a common batterycircuit which is permanentlyclosed and provided With battery, one or more A'individualtelephone-lines normally connected to earth at each local stationlthrough a call-bell, means forcutting out the call-bell and connectingsaid individual line to the battery-circuit, and a telephoneswitch foralso cutting the individual line and connecting it through a branchincluding the secondary coil ofthe transmitter.

7. The combination, at the central station, of 7'5 means for receiving asignal from any local station, means for disconnecting the individualline from its normal earth and for connecting said line to the commonbattery-line for calling the local station, and means fordisconnectingthe normal earth of theindividual line and for connectingsaid individual line vthrough a branch at the central station includinga telephone-receiver and their secondary coil of a transmitter whoseprimary coil is in the battery-circuit.

8. A series of individual telephone-lines which center at a centralofce,tWo normallyopen branches for each individual line at said centraloffice, means for connecting said branches to said individual line, oneto connect said individual line to a `colnmon battery-circuit and theother to connect the individual line to earth through atelephonicreceiver and transmitter, all in combination as described.

9. In a telephone system, the combination, at a central station, of aseries of main lines, a common battery-line, a normally-open branch forjoining any individual line to the batterycircuit, a secondnormally-open branch independent of the battery-line,containingiatelephonic transmitter and receiver to which any individualline may be joined after it is broken from its normal earth, and meansfor disconnectin g 'the individual lines from their earthconnections atthe central otlice and joining them together in pairs.

Executed May 25, 1883.

WILLIAM H. ECKERT. JOHN A. SEELY.

Vitnesses:

WM. B. VANsrzn, WM. ARNoUX.

IOO

